03-09-2014, 12:51 PM
PNEUMATIC ROBO ARM
PNEUMATIC ROBO.pptx (Size: 656.59 KB / Downloads: 23)
INTRODUCTION
Nowadays robots are flourishing in many industries. In olden days robots are only used as toys for children, but today it finds a wide range of applications in most of the industries, companies, hospitals, etc., for automation purposes. Mostly stepper motor is used to control the arm for the robots. So we innovate our idea to replace stepper motor by pneumatics. We use pneumatics for the advantage of heavy torque comparing to stepper motor.
Directional Control Valve
The 5/2-way valve has 5 ports and two positions. The 5/2-way valve is used primarily as a control element for the control of cylinders.
An example of the 5/2-way valve, the longitudinal slide valve uses a pilot spool as a control component. This connects or separates the corresponding lines by means of longitudinal movements. The resulting actuation force is lower because there are no opposing forces due to a spring or compressed air.
All forms of actuation can be used with longitudinal slide valves, i.e. manual, mechanical, electrical or pneumatic. These types of actuation can also be used for resetting the valve to its starting position.
Pneumatic Cylinders
The pneumatic power is converted to straight line reciprocating motion by pneumatic cylinders. The various industrial applications for which air cylinders are used can be divided dutywise into three groups — light duty, medium duty and heavy duty. But according to the operating principle, air cylinders can be sub-divided as single acting and double acting cylinders.
Single Acting Cylinder
In a single acting cylinder, the compressed air is fed only in one side. Hence, this cylinder can produce work only in one direction. The return movement of the piston is
effected by a built-in spring or by application of an external force.
Double Acting Cylinder
In a double acting cylinder, the force exerted by the compressed air moves the piston in either of the two directions. They are used particularly when the piston is required to perform work not only on the advance movement but also on the return. In principle, the stroke length is unlimited, although buckling and bending must be considered before we select a particular size of piston diameter, rod length and stroke length.
WORKING
When the air is supplied to the piston of lower arm by using DC valve, the arm lifts upward. When the air is supplied to the fore arm piston by using DC valve, the fore arm lifts. The fore arm is used to increase the picking or placing distance. An wiper motor is fixed at the base of the arm to give the oscillation. This wiper motor is controlled by using a battery and switch. A gripper used to picking and placing is controlled by another piston and DC valve.
At first the compressor is turned on, this causes the compressor to fill the compressed air in the reservoir. The compressed high pressure air then reaches the FRL unit. Here the air is filtered, regulated and lubricated to send it to the system. In the system the air first reaches the junction valve. From the junction valve the air is send to each DC valve and stops in there to actuate the piston when needed. Then the wiper motor switch is on. Now the arm fixed to the wiper oscillates. By off the switch the wiper is stopped in correct position. Now the DC valve of the forearm and lower arm is actuated. This causes the arms to move downward to pick the work. Then the grippers piston is actuated to open the jaw. Now the arms are move to downwards to a small
ADVANTAGES
Very reliable components.
Simplicity of Design and Control.
Compressed air does not possess fire or explosion risk so it is suitable for industrial purpose.
Back force on a servo motor or stepper motor can damage the gears, but pneumatic actuator will not have the same harmful effect.
Flexible and easy to install.
Compressed air can be stored in a tank which allows operation even when power is lost.
APPLICATIONS
Used in handling of harmful chemicals instead of humans.
Used in places where the temperature is not suitable for humans.
Used in explosive environment instead of electrical pick and place arms.
Used in handling very large and light weight objects.
Used in places where any pneumatic system works. This reduces the cost.